This invention relates to a grain stalk lifter for use with combines when combining grain stalks which are lying down because of either weather, or insects such as the saw-fly.
Lifters have been known and used for a long time with agricultural machines. The prior art appears to break down into two major categories: those lifters that use only a springy rod for lifting, and those lifters that use a more complicated, manufactured device attached to the harvester.
U.S. Pat. No. 741,314, U.S. Pat. No. 1,956,676, U.S. Pat. No. 3,209,526, and U.S. Pat. No. 4,704,850 are representative of the first category. These patents all use a springy rod to pick up downed agricultural material for harvesting. If the forwardly projecting rod breaks as the harvester moves forward through the fields, there is a very great likelihood that pieces of the broken rod itself will be ingested into the harvester. When this happens with a conventional combine, substantial internal damage to the combine usually occurs. The likelihood of this problem occurring increases as the harvesting speed of a combines increases.
There is another problem associated with all the inventions cited: these inventions are not easily attached to a grain harvesting combine. In each patent cited above, the patent describes devices that were designed to be attached to different types of harvesting equipment.
In the second category, manufactured devices, several patents are representative: for instance see U.S. Pat. No. 2,317,127, U.S. Pat. No. 2,970,420, and U.S. Pat. No. 3,753,339. Again these patents all illustrated devices that project forward of the machine near ground level as the machine moves forward through a field. But they each illustrate a more complicated lifter. The likelihood of ingesting broken lifter parts is just as great as before. But in each case, there are different materials associated with the lifters themselves. Although not generally required by the patents, some of the parts are most easily shaped using metal like iron or steel.
The bigger problem however, is that the devices shown in the '127, and '339 patents could not be attached in a meaningful way to a conventional grain combine. The device shown in the '420 patent might be adapted to fit a grain combine, but this device requires a separate, dedicated, rotating drive shaft positioned below the cutting bar of the combine to operate. This drive shaft drives teeth on a continuous chain, internal to the lifter, so that the teeth move backward at a rate approximately equal to the forward speed of the combine over the field.
Something simpler is needed. All of the lifters cited, since they are facing downward in the direction of motion, have a significant tendency to dig into the ground and break off. Breaking the lifters off is a significant, and expensive, problem. Since a conventional grain combine moves at a few miles per hour while harvesting, any ingested parts broken from the forward facing lifters need to be made of a softer material than spring steel. Such a change can substantially limit the internal damage to the combine. In addition, these new lifters need to be passive devices which can be easily attached, or moved, along the cutting bar of a grain combine for spacing. If moving parts can be eliminated, it is believed that the overall reliability of a new lifting device could be improved substantially over those lifters that require more complex, internal, moving parts. A return to some type of simple, passive device is needed.